The timing of the injection is not right as puppies mainly rely on maternal antibodies obtained from breast milk to fight against viruses. Dogs that leave breast milk early may already be infected with viruses before their first immunization, and high levels of maternal antibodies can neutralize the effect of the vaccine, making immunization unsuccessful, so the timing of the first immunization is important. Inadequate antibody immunizations are designed to allow the body to produce antibodies to fight the virus. A serum antibody titer of more than 10 international units per milliliter is required to prevent infectious diseases. Therefore, when antibodies are not produced or titers are relatively low before all injections are completed, there is still a possibility of contracting the disease. If the virus or bacterial strain has mutated, immunization will also fail. For example, if the canine microvirus has undergone several genetic drifts, the vaccine made from the original strain will not provide protection. Vaccine quality problems Currently, the commonly used virus vaccines in China are mainly divided into two categories: weak and inactivated vaccines, which can produce strong and long-lasting immune effects if successfully vaccinated, but are prone to stability problems due to impurity of the strain; inactivated vaccines are relatively safe, but their effects are weak and may require multiple injections to produce sufficient antibodies. Vaccine transportation and storage problems Vaccines cannot guarantee low temperature during transportation and storage; vaccines are removed and exposed to direct sunlight before immunization or removed for too long, resulting in reduced vaccine activity, and all kinds of problems can cause immunization failure. Improper vaccine use Vaccine is not released with special dilution solution according to the instructions for use, or not used up within the specified time after dilution, thus causing the stability of vaccine to be greatly reduced; in the process of vaccine dilution or vaccination, too much disinfection drug remains on the syringe or the disinfection drug directly touches the vaccine, resulting in vaccine failure or reduced effectiveness; unprofessional vaccine injectors Vaccine injectors are not professionally trained, and the injection operation is not skilled, resulting in vaccine failure. The vaccinators are not professionally trained, not proficient in the operation of injection, miss the injection and cause inaccurate dose of immunization, do not follow the prescribed method of vaccination, etc., all of which can cause vaccination failure. Immunization failure can be caused by the poor condition of the immunized pet, such as stress caused by transportation, bathing, environmental changes, etc. Immunity is reduced, malnutrition, failure to undergo internal and external deworming procedures, viral infection or incubation period, early serum injection by unscrupulous businessmen, etc.
